1. Field of the Invention
The present invention relates to heat treatment methods for sliding bearings made of age-hardened aluminum materials, or the like, and more particularly, to heat treatment methods for sliding bearings used in swash plate-type compressors.
2. Description of Related Art
Age-hardened aluminum materials, e.g., artificially age-hardened aluminum alloys, may be used in the manufacture of components of swash plate-type compressors, e.g., pistons, swash plates, or the like, to produce components of sufficient hardness, but lighter weight than components made of other metals, e.g., ferrous metals, such as steel, or the like. The age-hardened aluminum materials may be coated with a thermoplastic resin, or a solid lubrication material that may include a thermoplastic resin as a binder, to form sliding bearings, e.g., sliding bearing portions of pistons, swash plates, or the like. Moreover, the thermoplastic resin, or the solid lubrication material comprising a thermoplastic resin as a binder, may be calcined. The calcination temperature of the thermoplastic resin, or the solid lubrication material comprising a thermoplastic resin as a binder, is substantially the same as the age-hardening temperature of the aluminum materials, e.g., age-hardened aluminum alloys. As a result, the age-hardened aluminum materials may experience a decrease in hardness from overaging due to the calcination treatment.
A need has arisen to provide a heat treatment method for sliding bearings made of age-hardened aluminum materials, which method reduces or eliminates overaging of the age-hardened aluminum materials.
In an embodiment of the present invention, a heat-treated sliding bearing made of an age-hardened aluminum material comprises an aluminum material, wherein the aluminum material is artificially age-hardened for a time that is less than a time specified for reaching a maximum hardness. Moreover, a coating of a thermoplastic resin is placed on a surface of the aluminum material and the coating is calcined.
In further embodiment of the present invention, a heat-treated sliding bearing made of an age-hardened aluminum material comprises an aluminum material, wherein the aluminum material is artificially age-hardened for a time that is less than a time specified for reaching a maximum hardness. Moreover, a coating of a solid lubrication material comprising a thermoplastic resin as a binder is placed on a surface of the aluminum material, and the coating is calcined.
In a still further embodiment of the present invention, a method of heat treating sliding bearings made of an age-hardened aluminum material comprises the steps of age-hardening an aluminum material for a time that is less than the time specified for reaching a maximum hardness of the aluminum material, coating the aluminum material with a substance, and calcining the substance. The substance may comprise a thermoplastic resin, or a solid lubrication material comprising a thermoplastic resin as a binder. Moreover, a heat-treated sliding bearing made according to this method, is disclosed in yet another embodiment of the present invention.
Other objects, features, and advantages of this invention will be apparent to, and understood by, persons of ordinary skill in the art from the following description of preferred embodiments with reference to the accompanying drawing.